1. Field of the Invention
The present invention relates to a colored curable composition containing a dye, suitable for forming a color filter to be used for a liquid crystal display element or a solid state image pickup element, a dye-containing color filter, and a production method thereof.
2. Description of the Related Art
As a color filter to be formed on a device for realizing a color structure in a solid state image pickup element or a liquid crystal display element, there is known a color filter in which different layers of the color filter are formed in a mutually adjacent manner in a same plane on a substrate. As examples of such a color filter, there are known a color filter constituted of a yellow filter layer, a magenta filter layer and a cyan filter layer, and a color filter constituted of a red filter layer, a green filter layer and a blue filter layer, in which such filter layers are formed in striped patterns or in mosaic patterns.
For producing such color filter, there have been proposed various production methods. Among these, so-called color resist method is widely practiced, in which a patterning process of exposing and developing a dye-containing photosensitive resin composition is repeated by a necessary number of times.
Such color resist method prepares a color filter in a photolithographic process utilizing radiation-sensitive coloring compositions in which pigments are dispersed in various photosensitive compositions, and is considered suitable for preparing a color filter for color displays of a large size and high definition, since it can provide high resistances to light and heat because of the use of pigments and it can provide a sufficient positional precision by photolithographic patterning.
In the case of preparing a color filter by the pigment dispersion method utilizing a pigment dispersion, a radiation-sensitive composition is coated on a glass substrate by a spin coater or a roll coater to obtain a coated film, which is pattern exposed and developed to obtain colored pixels, and the color filter is obtained by repeating such operations for the desired number of colors. Within such pigment dispersion method, a negative-working photosensitive composition utilizing a photopolymerizable monomer and a photopolymerization initiator in combination with an alkali-soluble resin is disclosed in, for example, Japanese Patent Application Laid-Open (JP-A) Nos. 1-102469, 1-152499, 2-181704, 2-199403, 4-76062, 5-273411, 6-184482, 7-140654 and 2002-14222.
However, recently a higher definition is desired for the color filter for use in solid state image pickup elements. Prior pigment dispersion systems, as described above, are incapable of improving the resolution, also, there are associated drawbacks such as unevenness in color due to the presence of coarse pigment particles, and are therefore unsuitable for applications requiring a fine pattern, such as solid state image pickup elements.
To deal with the above-mentioned problems, use of dyes has conventionally been proposed in, for example, JP-A Nos. 6-75375 and 2002-14221, and Japanese Patent Application Publication (JP-B) No. 7-111485.
Also, mixtures of violet dyes and cyan dyes are used for blue color filter arrays of color filters are known in, for example, JP-A No. 2002-14222.
However, dyes containing curable compositions have been associated with the following drawbacks and further improvements have been desired.                (1) Dyes are generally inferior in heat resistance and light resistance compared to pigments, and is thus unsatisfactory in fading resistance;        (2) When a dye has a low molar absorption coefficient, it is required to add the dye in a large amount, whereby other components in the curable composition, such as a polymerizable compound, a binder and a photopolymerization initiator, have to be relatively decreased, thereby resulting in deteriorations in the curing property of the composition when curing, heat resistance of cured portions of the composition or developability of uncured portions; and        (3) Dyes often shows interactions with other components in the curable composition, whereby it is difficult to regulate the developability (solubility) of cured portions and uncured portions.        
Thus, the dyes that have been employed in the photosensitive composition are not satisfactory in the fading stability, and, having a low solubility in the photosensitive composition, may show a precipitation in a liquid state or in a coated film and cannot be easily contained at a high concentration.
As described, with respect to dye conventionally used for a photosensitive composition, it is generally unsatisfactory in fading resistance, inferior in solubility in the photosensitive composition, and difficult to add at a high concentration.
Further, as described above, dyes for forming mixtures to be used for blue filter arrays are insufficient in heat resistance and light resistance and it is desired to improve the properties.
Also, dyes for forming mixtures to be used for blue filter arrays are insufficient in heat resistance and light resistance and improved properties are desired.